Species InteractionTori Teoh, Skylar Masuda, Heather Osterstock,

Lea Sado, Juliane Venezuela, Liana Garcia

What makes a species?

You Must Know

● The concept of a niche and how it is

affected by competition.

● The role of competitive exclusion in

interspecific competition.

● The symbiotic relationships of

parasitism, mutualism, and

commensalism.

● Species diversity has two components:

species richness and relative

abundance.

● The impact of keystone species on

community structure

● The difference between primary and

secondary successions.

Community Interactions

Categorized as positive relationships:

Or negative relationships:

(+/+) or (+/0)

(+/-) or (-/-)

Mutualism (+/+)

Commensalism (+/0)

Negative Relationships

Predation (+/-)

Herbivory (+/-)

Parasitism (+/-)

Competition (-/-)

Interspecific Competition

Competition for resources in short

supply. A neg/neg interaction

between species.

Competitive Exclusion Principle: two species competing for the same limiting resources cannot coexist permanently in the same place.

Ecological Niches

Fundamental NicheRealized Niche

How competitions affects niche

● Predation

○ Both prey and predator adapting to each other

● Herbivory

○ Prey adapt to predators likes, predators adapt to

prey’s protection

● Parasitism

○ Changes/ directly affects host

● Mutuilism

○ “Benefits to each partner must

exceed costs”

● Commensalism

○ “One-sided relationship”

Keystone SpeciesA keystone species is a species that

plays a crucial role in an ecosystem.

Without it, many ecosystems would

be drastically changed or be unable to

function.

Why are they so important?

● Keystone species have low

functional redundancy, meaning

it is unlikely that other species in

their ecosystems serve the same

purpose or fill the same niche.

● Often, keystone species are

predators who keep populations

in check.

● Sometimes, keystone species are

mutualists, such as pollinators,

who benefit other species that

more directly.impact the

ecosystem.

Examples!